1. Field of the Invention
The present invention relates to underground mining and, more particularly, to the design of supports for roof control at underground openings.
2. Description of Related Art
In the mining industry, steel set are generally installed at underground openings such as slope, belt entry, or caved area which require a reliable and long-term support for the roof to protect mine personnel and equipment. However, there are currently no steel set design guidelines and methodologies available that have been well-established to meet engineering needs in the underground mining industry. Historically, steel set designs were based on trial-and-error and field experiences. The majority of steel sets or supports installed typically perform well due to the over-design and excessive safety factor purposely adopted by engineers, which result in unnecessary financial investment and a waste of steel and other resources. On the other hand, less conservative steel set design may provide a structure that cannot provide adequate roof support, which can result in unexpected roof falls causing personnel injuries, equipment damages, and economic loss due to extended production down time.
Further, other design practices adopt a steel structure design method in civil engineering to design steel set. However, such practices generally over-simplify steel set design and ignore the effect of ground pressure variation caused by changing geological conditions in the vicinity of an opening. Therefore, a practical and reliable steel set design methodology is needed which takes into account the effect of geological conditions; identifies technically and economically optimal steel set per field condition and engineering needs; designs the most reliable steel set structure; and can verify the adequacy of the developed steel set.
U.S. Pat. No. 6,832,165 to Stankus et al. is generally directed to a method for predicting potential mine roof failures including the steps of identifying relevant factors that affect mine roof stability; quantifying and weighing each relevant factor; and calculating a roof instability rating (RIR) value based upon the quantified relevant factors.
U.S. Pat. No. 5,824,912 to Stankus et al. is generally directed to a method for designing roof control in an underground mine including the steps of obtaining mechanical properties of the mine site, applying the mechanical properties to a layout of a mine in the mine site, and determining from the application of the mechanical properties, stresses in the mine site.